MONITORING CONDITION OF ELECTROCHEMICAL CELLS

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Disclosed herein are methods, systems, and computer programs that relate to monitoring condition of one or more electrochemical cells or a group of the electrochemical cells in one or more electrolyzers.

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Description
CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit to U.S. Provisional Patent Application No. 62/463,124, filed Feb. 24, 2017, which is incorporated herein by reference in its entirety in the present disclosure.

BACKGROUND

Monitoring systems and processes is gaining increasing attention and importance in both industry and academia. The monitoring of electrochemical cells in an electrolyzer may provide accurate and immediate information on variables that describe the state of a reaction in the process. There is a considerable demand for the monitoring of the electrochemical cells in an electrolyzer for process development, pilot plant operation, and monitoring of industrial manufacturing processes.

SUMMARY

In one aspect, there is provided a method for monitoring condition of one or more electrochemical cells in an electrolyzer, the method comprising:

characterizing a reference voltage range for one or more electrochemical cells in an electrolyzer during operation, wherein the one or more electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;

acquiring a voltage of the one or more electrochemical cells during the operation;

comparing the acquired voltage with the reference voltage range based on the factors; and

generating an alarm trigger when the acquired voltage deviates from the reference voltage range, thereby monitoring the condition of the one or more electrochemical cells in the electrolyzer.

In some embodiments of the above noted aspect, further comprising determining the concentration of the metal ions in the anolyte of the one or more electrochemical cells and based on the determination, characterizing the reference voltage range for the one or more electrochemical cells. In some embodiments of the above noted aspect and embodiments, comprising determining the concentration of the metal ions in the feed anolyte and/or exit anolyte from the one or more of the electrochemical cells in the electrolyzer.

In some embodiments of the above noted aspect and embodiments, the characterizing the reference voltage range comprises characterizing the reference voltage range versus current distribution and determining the acquired voltage comprises determining the acquired voltage versus current distribution during the operation of the one or more electrochemical cells.

In some embodiments of the above noted aspect and embodiments, the factors further comprise temperature, pressure, flow rate, and combinations thereof.

In some embodiments of the above noted aspect and embodiments, the anolyte further comprises salt ions and the factors further comprise concentration of the salt ions in the anolyte during the operation of the one or more electrochemical cells. In some embodiments, the salt ions are alkali metal salt ions or alkaline earth metal salt ions. In some embodiments, the salt ions are alkali metal salt ions or alkaline earth metal salt ions and halide ions.

In some embodiments of the above noted aspect and embodiments, the concentration of the metal ions in the anolyte comprises concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the metal ion is copper (Cu).

In some embodiments of the above noted aspect and embodiments, the concentration of the metal ions comprises concentration of Cu(I), concentration of Cu(II), concentration of total Cu(I) and Cu(II), ratio of the concentration of Cu(I) to Cu(II), or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the metal ion is in form of a metal halide.

In some embodiments of the above noted aspect and embodiments, the method further comprises obtaining data from in-situ or ex-situ analytical techniques and based on the data determining the concentration of the metal ions and/or the concentration of the salt ions in the anolyte during the operation. In some embodiments, the in-situ or ex-situ analytical techniques comprise coriolis meter, titration of the anolyte, inductively coupled plasma (ICP) technique, ultra-microelectrode (UME) technique, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the operation comprises start-up, shut-down, steady state, transient state, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, generating the alarm trigger comprises generating an alarm to analyze the one or more electrochemical cells in the electrolyzer; generating interlock protocol; generating shut-down protocol; or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the method further comprises classifying the one or more electrochemical cells as significantly damaged, damaged, or undamaged, based on the comparison or the alarm trigger.

In some embodiments of the above noted aspect and embodiments, the method further comprises measuring a physical parameter of the one or more electrochemical cells classified as significantly damaged or damaged, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the method further comprises based on the measurement, evaluating: size and position of a pinhole in a membrane in the cell; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the method further comprises taking a maintenance action on the one or more electrochemical cells based on the evaluation.

In one aspect, there is provided a system for monitoring condition of one or more electrochemical cells in an electrolyzer, the system comprising:

a voltage acquisition module coupled to each one of electrochemical cells or a group of the electrochemical cells in an electrolyzer and adapted for characterizing a reference voltage range and for acquiring voltage for each one of the electrochemical cells or the group of the electrochemical cells during operation, wherein each one of the electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;

a factor acquisition module adapted for acquiring data related to the factors comprising the current density and the concentration of the metal ions in the anolyte of the one or more electrochemical cells;

a comparison module coupled to the voltage acquisition module and the factor acquisition module, the comparison module adapted to compare the acquired voltage with the characterized reference voltage range based on the factors; and trigger an alarm when the acquired voltage deviates from the reference voltage range.

In some embodiments of the above noted aspect, the anolyte further comprises salt ions and the factors further comprise concentration of the salt ions in the anolyte of the one or more electrochemical cells.

In some embodiments of the above noted aspect and embodiments, the factor acquisition module is adapted to acquire data related to the factors comprising the current density, concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, and/or concentration of the salt ions.

In some embodiments of the above noted aspect and embodiments, the metal ion is Cu.

In some embodiments of the above noted aspect and embodiments, the operation comprises start-up, shut-down, steady state, transient state, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the comparison module is adapted to trigger the alarm by sound, by generating interlock protocol, by generating shut-down protocol, or combinations thereof. In some embodiments of the above noted aspect and embodiments, the comparison module is further adapted to classify the cells as significantly damaged cells, damaged cells, and undamaged cells, based on the comparison.

In some embodiments of the above noted aspect and embodiments, the system further comprises a storage module coupled to the voltage acquisition module; the factor acquisition module; and the comparison module, adapted for storing: the reference voltage range for each one of the cells; the acquired voltage for each one of the cells; the concentration of the metal ions in the anolyte of the one or more electrochemical cells; the concentration of the salt ions in the anolyte of the one or more electrochemical cells; current density; and the comparison data.

In some embodiments of the above noted aspect and embodiments, the voltage acquisition module comprises a current controlling module, the current controlling module being adapted to control current in each one of the cells or group of cells at start-up, steady state, shut-down, and/or transient state of the cells.

In some embodiments of the above noted aspect and embodiments, the system further comprises a damage evaluation module coupled to the comparison module, the damage evaluation module adapted to obtain information from one or more sensors adapted for measuring a physical parameter of each one of the cells classified as significantly damaged cells or damaged cells, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, the damage evaluation module is adapted for evaluating at least one of a position and size of a pinhole in a membrane; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof, using the measured physical parameter for each one of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, the system further comprises an electrolyzer maintenance module coupled to the damage evaluation module and adapted to transmit a signal representative of a maintenance action to be performed on any one of the significantly damaged or damaged cells, the maintenance action being based on the evaluation of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, the sensor comprises one of a differential pressure sensor and/or a liquid sensor for measuring a level or flow of liquid in a cell.

In one aspect, there is provided a computer program product encoded on a non-transitory computer-readable medium, which when executed, causes the computer to monitor condition of one or more electrochemical cells in an electrolyzer, which computer program product comprises:

instructions executable to characterize reference voltage range for each one of electrochemical cells in an electrolyzer during operation, wherein each one of the electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;

instructions executable to acquire voltage for each one of electrochemical cells in an electrolyzer during operation;

instructions executable to acquire data related to the factors comprising the current density and the concentration of the metal ions in the anolyte during the operation of the one or more electrochemical cells;

instructions executable to compare the acquired voltage with the characterized reference voltage range based on the factors; and

instructions executable to trigger an alarm when the acquired voltage deviates from the reference voltage range.

In some embodiments of the above noted aspect, the instructions executable to trigger the alarm comprise triggering the alarm, generating interlock protocol, generating shut-down protocol, or combinations thereof.

In some embodiments of the above noted aspect and embodiment, computer program product further comprises, based on the comparison, instructions executable to classify the cells as significantly damaged cells, damaged cells, and undamaged cells.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to store information comprising the reference voltage range for each one of the cells; the acquired voltage for each one of the cells; the concentration of the metal ions in the anolyte of the one or more electrochemical cells; the concentration of salt ions in the anolyte of the one or more electrochemical cells; current density; and the comparison data.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to obtain information from one or more sensors adapted for measuring a physical parameter of each one of the cells classified as significantly damaged cells or damaged cells, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to evaluate at least one of a position and size of a pinhole in a membrane; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof, using the measured physical parameter for each one of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to transmit a signal representative of a maintenance action to be performed on any one of the significantly damaged or damaged cells, the maintenance action being based on the evaluation of the significantly damaged or damaged cells.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention may be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

FIG. 1 is an illustration of some embodiments of the electrochemical cell in the electrolyzer.

FIG. 2 is an illustration of some embodiments of the monitoring methods described herein.

FIG. 3 is an illustration of some embodiments of the reference voltage range and the acquired voltage described herein.

FIG. 4 is an illustration of some embodiments of the monitoring systems described herein.

FIG. 5 is an illustration of some embodiments described in Example 2 herein.

 DETAILED DESCRIPTION

Disclosed herein are systems, methods, and computer program products that relate to the monitoring of the electrochemical cells in an electrolyzer system by monitoring the voltage of the electrochemical cells and its dependence on other factors of the system; to identify the damaged or underperforming cells; and to provide maintenance to the cells.

Before the present invention is described in greater detail, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

Certain ranges that are presented herein with numerical values may be construed as “about” numerical. The “about” is to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrequited number may be a number, which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, representative illustrative methods and materials are now described.

All publications and patents cited in this specification are herein incorporated by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference and are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

It is noted that, as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present invention. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.

Methods and Systems

The methods and systems provided herein for the monitoring of the electrochemical cells in the electrolyzer relate to any electrochemical cell that comprises metal ions in the anolyte in the anode chamber of the cell and where the anode oxidizes the metal ions from lower oxidation state to the higher oxidation state. The methods and systems provided herein comprise the detection of cells with damage to their components such as, pinhole in ion exchange membranes, pinched tubes, broken parts, welded joints, etc. and with lower voltage efficiency. With such a diagnosis, better overall electrolysis efficiency of the electrolyzer can be achieved through rearranging/replacement/decommissioning of the damaged cells in the electrolyzer.

Illustrated in FIG. 1 is an example of an electrochemical cell 100 in the electrolyzer, as monitored by the methods and systems provided herein. The “cell” includes the smallest group of anodes and cathodes that are connected to the same current feeder. The ways the anodes, cathodes and membrane are connected differ according to the selected technology. For example, the electrodes can be connected in parallel, in series, or a combination thereof. For example, a bipolar electrolyzer has a plurality of cells.

The electrolyzer may have any number of the electrochemical cells and there may be any number of the electrolyzers in a plant. There is an anode in contact with an anode electrolyte or anolyte in an anode chamber and a cathode in contact with a cathode electrolyte or catholyte in a cathode chamber, in the electrochemical cell provided herein. The anode and the cathode may be separated by one or more ion exchange membranes (IEM). The IEM may be an anion exchange membrane (AEM), a cation exchange membrane (CEM), or both. In some embodiments, where both the AEM and the CEM are present, a middle chamber is formed between the AEM and the CEM that comprises an electrolyte. The electrochemical cell comprises an anode in contact with an anode electrolyte wherein the anode electrolyte comprises metal ions in an aqueous medium such as salt water; a cathode in contact with a cathode electrolyte; and a current source configured to apply current to the anode and the cathode wherein the anode is configured to oxidize the metal ion from a lower oxidation state to a higher oxidation state.

The anode chamber of the electrochemical cell illustrated in FIG. 1 has anode that, on the application of current at the anode and the cathode, oxidizes metal ions from the lower oxidation state to the higher oxidation state. The process has been described in detail in U.S. Pat. No. 9,187,834, issued Nov. 17, 2015; U.S. Pat. No. 9,200,375, issued Dec. 1, 2015; and U.S. patent application Ser. No. 14/446,791, filed Jul. 30, 2014, all of which are incorporated herein by reference in their entireties in this application.

The anode or the anolyte comprises metal ions (illustrated as M in FIG. 1) which are oxidized at the anode from lower oxidation state ML+ to the higher oxidation state MH+. For example only, in the electrochemical cell oxidation of metal ions, such as, metal halides from a lower oxidation state to a higher oxidation state occurs in the anode chamber of the electrochemical cell. In some embodiments, the anolyte further comprises salt ions in water. The salt ions comprise alkali metal ions such as, for example only, alkali metal halide or alkaline earth metal ions such as, for example only, alkaline earth metal halide. Examples of salts include, without limitation, potassium chloride or sodium chloride or lithium chloride or magnesium chloride or calcium chloride or strontium chloride or ammonium chloride, or sulfate equivalents of these salts, and the like. Other salts of the alkali metal ions or alkaline earth metal ions are well within the scope of the invention. The salt ions may also be present in the catholyte. Therefore, this salt solution can be used as an anode electrolyte, cathode electrolyte, and/or brine in the middle compartment. Accordingly, to the extent that such equivalents are based on or suggested by the present system and method, these equivalents are within the scope of the description.

In such electrochemical cells, cathode reaction may be any reaction that does or does not form an alkali in the cathode chamber. Such cathode consumes electrons and carries out any reaction including, but not limited to, the reaction of water to form hydroxide ions and hydrogen gas; or reaction of oxygen gas and water to form hydroxide ions; or reduction of protons from an acid such as hydrochloric acid to form hydrogen gas; or reaction of protons from hydrochloric acid and oxygen gas to form water, etc.

As used herein, the current includes current applied to or drawn from an electrochemical cell that drives a desired reaction between the anode and the cathode in the electrochemical cell. Once the cell reaches a certain voltage based on the voltage of the reactions and resistive loses, the voltage is acquired during operation in accordance with methods and systems provided herein. In the electrochemical cell illustrated in FIG. 1, the desired reaction is the oxidation of the metal ions from the lower oxidation state to the higher oxidation state. The current may be applied to the electrochemical cell by any means for applying the current across the anode and the cathode of the electrochemical cell. Such means are well known in the art and include, without limitation, devices, such as, electrical power source, fuel cell, device powered by sun light, device powered by wind, and combinations thereof.

The voltage of the electrochemical cell at which the desired reaction takes place may be dependent on several factors, including but not limited to, current density, concentration of the metal ions in the anolyte, concentration of the salt ions in the anolyte, amount of water in the anolyte and catholyte, ratio of the metal ions concentration in the lower oxidation state to the metal ion concentration in the higher oxidation state in the anolyte, temperature, pressure, differential pressure, pH, flow rate, etc. The voltage may also vary depending on the stages of the operation such as start-up, shut-down, transient state, or steady state, etc. Any number of problems may occur in the electrochemical cells during operation which may result in inefficiencies and damage of the electrochemical cells. It may be challenging to devise a method to monitor the conditions of the electrochemical cells during operation due to several parameters of the electrochemical process. Applicants have devised a unique method/system/computer program product to monitor the condition of the electrochemical cells by monitoring the voltage as well as its dynamic dependence on the concentration of the metal ions in the anolyte and optionally other factors, in the electrochemical cells.

In one aspect, there is provided a method for monitoring condition of one or more electrochemical cells in an electrolyzer, the method comprising:

characterizing a reference voltage range for one or more electrochemical cells in an electrolyzer during operation, wherein the one or more electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;

acquiring a voltage of the one or more electrochemical cells during the operation;

comparing the acquired voltage with the reference voltage range based on the factors; and

generating an alarm trigger when the acquired voltage deviates from the reference voltage range, thereby monitoring the condition of the one or more electrochemical cells in the electrolyzer.

In some embodiments, the systems and methods provided herein for monitoring the condition of the one or more electrochemical cells in the electrolyzer relate to an on-line and real time monitoring of the cells. The on-line monitoring includes real time retrieval and analysis of data related to a process/system and dynamic control of the process/system to ensure desired operation. The on-line monitoring can supply process information in real time that enables efficient monitoring and control of the cells. While the on-line monitoring method/system may be fully or partially automated, the method/system may involve off-line techniques where the sample may be transported to a remote or centralized laboratory for analysis. In some embodiments of the methods and systems provided herein, the on-line monitoring method/system is fully automated. In some embodiments of the methods and systems provided herein, the on-line monitoring method/system is partially automated.

FIG. 2 illustrates some of the steps of the methods as provided herein. It is to be understood that the order of the steps may be changed and one or more steps may be omitted depending upon the desired process.

The methods provided herein comprise characterizing the reference voltage range for the one or more electrochemical cells in the electrolyzer during the operation (step II in FIG. 2), wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells. The methods provided herein further comprise determining the concentration of the metal ions in the anolyte of the one or more electrochemical cells and based on the determination, characterizing the reference voltage range for the one or more electrochemical cells (step I in FIG. 2). The steps I and II may interchange in order or may be simultaneous. In some embodiments, the step of determining the concentration of the metal ions in the anolyte of the one or more electrochemical cells may be simultaneous with a step of determining the current density of the cell. In some embodiments, characterizing the reference voltage range comprises characterizing the reference voltage range versus current distribution. The “reference voltage range” as used herein is a voltage range for an optimum efficiency of the operation of the one or more electrochemical cells. The reference voltage range of the electrochemical cell provided herein is dynamic or changing based on the current density as well as the concentration of the metal ions in the anolyte. For example, the reference voltage range is dynamically dependent on the concentration of the metal ions in the feed anolyte and/or exit anolyte from the one or more of the electrochemical cells in the electrolyzer.

For example, during operation, the anolyte with a certain concentration of the metal ions is fed to the anode chamber or exits the anode chamber. The exiting anolyte from the anode chamber may be used in other organic reactions where the metal ions may get reduced and the remaining metal ion solution is recirculated back to the anode chamber. Various organic reactions are known and an example of halogenation reaction using the metal ions has been described in U.S. Pat. No. 9,187,834, issued Nov. 17, 2015, which has been incorporated herein by reference in its entirety. Therefore, the concentration of the metal ions entering the anode chamber (after participating in other organic reactions) and the concentration of the metal ions exiting the anode chamber (after oxidation of the metal ions at the anode in the electrochemical cell) are constantly in flux. Depending on the rate of reactions and the process parameters, such as temperature, pressure, flow rates, water content, etc. there may be a change in the concentration of the metal ions in the feeding and exiting anolyte compositions. The methods and systems provided herein characterize the reference voltage range based on its dynamic dependence on the concentration of the metal ions. If there is any damage to the electrochemical cell (as described herein), there may be a change in the concentration of the metal ions which would affect the voltage of the cell. The deviation of the voltage from the reference voltage range may be then used to monitor the condition of the cells.

The concentration of the metal ions may be determined based on various in-situ or ex-situ analytical techniques described herein. The data obtained from the analytical techniques is used to determine the concentration of the metal ions in the anolyte being fed into the anode chamber or the anolyte exiting the anode chamber after the oxidation of the metal ions from the lower oxidation state to the higher oxidation state. The concentration of the metal ions include, without limitation, the concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, or combinations thereof. Based on the concentration of the metal ions (and the current density), the reference voltage range is characterized.

The methods provided herein further comprise acquiring a voltage of the one or more electrochemical cells during the operation (step III in FIG. 2). The “acquired voltage” as used herein is the voltage during the operation of the one or more electrochemical cells.

The methods provided herein further comprise comparing the acquired voltage with the reference voltage range based on the factors (step IV in FIG. 2). Based on the comparison, the methods further comprise generating an alarm trigger when the acquired voltage deviates from the reference voltage range (step V in FIG. 2). In some embodiments, the generating the alarm trigger comprises generating an alarm to analyze the one or more electrochemical cells in the electrolyzer; generating interlock protocol; generating shut-down protocol; or combinations thereof.

In the aspects and embodiments provided herein, the operation comprises start-up, shut-down, steady state, transient state, or combinations thereof. During the transient state of the operation, different current densities are applied from standard due to energy price fluctuations or market demands which would drive load shedding (reducing current density to lower production rates) or load increasing (increasing current density to increase production rates). The load shedding or load increasing may also be timed with respect to the time of the day. For example, load increasing in the night and load shedding in the day time to reduce energy costs.

FIG. 3 illustrates some embodiments of the methods and systems related to the comparison of the acquired voltage with the reference voltage range based on the factors. Solid line illustrates reference cell (or group of cell) voltage and upper and lower bounds indicate the reference voltage range. The reference voltage range is characterized depending on the anolyte composition such as, but not limited to, the concentration of the metal ions. The acquired voltage falling above or below this range would result in generating an alarm trigger and/or interlock protocol and/or shut-down protocol.

For example during the start-up of the cell or a group of cells in the electrolyzer, the cell currents are typically ramped up slowly (linearly or in steps) and the reference voltage range for specific anolyte compositions (e.g. concentrations of the metal ions) is characterized and used as reference within the system. In some embodiments, if during the start-up the acquired voltage deviates outside the reference voltage range an alarm may be triggered or the interlock protocol may be generated and the start-up may be changed or stopped, based on prescribed interlock controls.

As with start-up conditions, during steady state also the reference voltage range is characterized dependent on the anolyte composition (e.g. concentrations of the metal ions). In some embodiments, the time scales with voltage deviation (voltage deviation over time) may be longer depending on the problem in the cell which is measured and evaluated, as described below. In some embodiments, when the alarm is triggered, the operator may inspect the cell or group of cells manually in detail. In some embodiments, the methods and systems provided herein conduct an automated check of the physical parameters to check the conditions of the cells. In some embodiments, the voltage deviation may have shorter timescales and may signify something catastrophic happening with the cells in the period of seconds/minutes/hours. In this condition, the system may generate an alarm as well as initiate interlocks and shut-down protocols.

As explained herein, in the methods and systems provided herein, the anode is in contact with the anolyte comprising metal ions and the reference voltage range is dynamic dependent on the concentration of the metal ions in the anolyte of the one or more electrochemical cells. The “metal ion” or “metal” or as used herein, includes any metal ion capable of being converted from lower oxidation state to higher oxidation state. The metal ions may be in the form of any compound, for example only, metal halide, metal sulfate, etc. Examples of metal ions include, but not limited to, iron, chromium, copper, tin, silver, cobalt, uranium, lead, mercury, vanadium, bismuth, titanium, ruthenium, osmium, europium, zinc, cadmium, gold, nickel, palladium, platinum, rhodium, iridium, manganese, technetium, rhenium, molybdenum, tungsten, niobium, tantalum, zirconium, hafnium, and combination thereof. The “oxidation state” as used herein, includes degree of oxidation of an atom in a substance. For example, in some embodiments, the oxidation state is the net charge on the ion.

In some embodiments, the reference voltage range is dependent on the anolyte composition comprising the concentration of the metal ion in the lower oxidation state and the concentration of the metal ion in the higher oxidation state.

In some embodiments, the reference voltage range may also be dependent on the anolyte composition comprising the concentrations of the halide ions in combination with the concentration of the metal ions. In some embodiments, the reference voltage range may be dependent on the anolyte composition comprising the concentrations of the metal halide with metal ion in both lower as well as higher oxidation state.

In the embodiments of the methods and systems aspects provided herein, when the current is applied to the anode and the cathode of the electrochemical cells, the anode oxidizes metal ions from lower oxidation state to the higher oxidation state. Therefore, the anolyte comprises metal ions in the lower oxidation state as well as the same metal ions in the higher oxidation state. The concentration of the metal ions in different oxidation states changes in the anolyte as the anode oxidizes the metal ions. Accordingly, the reference voltage range dependent on the concentration of the metal ions in the anolyte exiting the anode chamber, is also dynamic.

In some embodiments of the methods and systems provided herein, the concentration of the metal ions in the anolyte comprises concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, or combinations thereof.

In some embodiments of the methods and systems provided herein, the metal ion is copper (Cu), iron (Fe), tin (Sn), or Nickel (Ni). In some embodiments of the methods and systems provided herein, the metal ion is copper (Cu). In some embodiments of the methods and systems provided herein, the metal ion is copper (Cu) in the form of metal compound copper chloride (CuCl and CuCl2). In some embodiments of the methods and systems provided herein, the concentration of the metal ions comprises concentration of Cu(I), concentration of Cu(II), concentration of total Cu(I) and Cu(II), ratio of the concentration of Cu(I) to Cu(II), or combinations thereof. In some embodiments of the methods and systems provided herein, the concentration of the metal ions comprises concentration of CuCl, concentration of CuCl2, concentration of total CuCl and CuCl2, ratio of the concentration of CuCl to CuCl2, or combinations thereof.

In some embodiments, the anolyte comprising metal ions further comprises salt ions. In some embodiments, the anolyte comprises metal ions, such as e.g. metal halide or metal sulfate in salt water. The metal ion may be present in any compound form such as metal halide, metal sulfate or any suitable metal compound. The salt ions may be any suitable salt including but not limited to, alkali metal ion, e.g. alkali metal halide or sulfate; or alkaline earth metal ion, e.g. alkaline earth metal halide or sulfate. Examples include, without limitation, salts of lithium, sodium, potassium, rubidium, caesium, francium, beryllium, magnesium, calcium, strontium, barium, and the like. The anion in the salt may be a halide (chloro, bromo, iodo, or fluoro), sulfate or any other suitable anion. Examples include without limitation, lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, etc.

In some embodiments, the reference voltage range is dynamic dependent on factors comprising the current density, the concentration of the metal ions, and the concentration of the salt ions. In some embodiments, the salt ions comprise salt cations as well as salt anions. In some embodiments, the salt ions comprise alkali metal ions and halide ions. In some embodiments, the salt ions comprise alkaline earth metal ions and halide ions. In some embodiments where the metal ion is metal halide and salt is alkali metal halide, the reference voltage range is dynamic dependent on the concentration of the metal ions, the concentration of the alkali metal ions, and concentration of the halide ions. In some embodiments where the metal ion is metal halide and salt is alkaline earth metal halide, the reference voltage range is dynamic dependent on the concentration of the metal ions, the concentration of the alkaline earth metal ions, and concentration of the halide ions.

In some embodiments, the methods comprise obtaining data from in-situ or ex-situ analytical techniques to determine anolyte composition (step I in FIG. 2). The anolyte composition comprises concentrations of the ions in the composition. The ions include metal ions and optionally salt ions. In some embodiments, the methods provided herein comprise obtaining data from in-situ or ex-situ analytical techniques and based on the data determining the concentration of the metal ions and/or the concentration of the salt ions in the anolyte during the operation. The in-situ or ex-situ analytical techniques include, but not limited to, coriolis meter, titration of the anolyte, inductively coupled plasma (ICP) technique, ultra-microelectrode (UME) technique, or combinations thereof. Many other in-situ or ex-situ analytical techniques have been described herein and are well known commercially.

Other factors that may affect the reference voltage range include temperature, pressure, flow of liquid in the cells, or combinations thereof. In some embodiments of the aforementioned aspects and embodiments, the temperature may be the temperature in any component of the process. For example, the temperature can be of the liquid streams in the electrochemical cell, of the gaseous products/byproducts, of the components of the process such as valves, pumps, compressors, etc. In some embodiments of the aforementioned aspects and embodiments, the pressure is the gauge pressure in any component of the process. For example, the pressure in the electrochemical cell and/or the pressure in the components of the process such as valves, pumps, compressors, etc. For example only, the pressure gauge may help in determining the differential pressure i.e. the pressure drop across the cells and/or to measure liquid flow in the cells. In some embodiments of the aforementioned aspects and embodiments, the flow may be the flow of different liquids or fluids in the tanks, vessels, conduits, pipes, etc. In some embodiments of the aforementioned aspects and embodiments, the density, concentration, flow rate, etc. can be of fluids and gases in and out of the electrochemical cell and/or fluids and gases flowing through the conduits.

As illustrated in FIG. 2, the methods provided herein further comprise classifying the one or more electrochemical cells as significantly damaged, damaged, or undamaged, based on the comparison or the alarm trigger (step VI in FIG. 2). If the acquired voltage of the cell is within the reference voltage range, the cells is considered undamaged. If the acquired voltage of the cell is outside of the reference voltage range by a small margin (is either higher than the upper range of the reference voltage range or lower than the lower range of the reference voltage range), the cell is considered damaged and the alarm trigger is generated prompting an inspection of the cell. If the acquired voltage of the cell is significantly outside of the reference voltage range, the cell is considered significantly damaged and the alarm trigger is generated also generating interlock and shut-down procedure. The significantly damaged cell may be deactivated, removed, replaced, or accessed for maintenance depending on the condition of the cell.

In some embodiments, the methods provided herein further comprise measuring or checking some physical parameters of the significantly damaged or damaged cells in order to determine the reason for the anomaly in the factors, such as concentration, temperature, pressure, etc. further affecting the voltage of the cells (step VII in FIG. 2). The physical parameters comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof. There may be several other physical parameters that can be measured and evaluated, all of which are within the scope of this application. The physical parameters may be measured manually, digitally, and/or automatically.

In some embodiments, the methods provided herein further comprise evaluating the components of the cells if an anomaly is detected in the measurement of the physical parameter (also step VII in FIG. 2). The evaluation includes evaluating various components of the cells including, but not limited to: membrane in the cell to locate size and position of a potential pinhole; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell to locate leaks or warping if any; welded points in the cell to locate poor electrical distribution; or combinations thereof. The evaluation may also be conducted manually, digitally, and/or automatically.

The occurrence of holes or tears in the cell membrane also called pinholes can cause damage to the cell dropping the cell efficiency. Some reasons for the presence of pinholes and pores in the cell membrane are the formation of voids, blisters, and delaminating of the membrane due to faults in start-ups and shut-downs and by contaminated electrolytes. The presence of pinholes in the membrane, for example, can affect the cell's efficiency in different ways depending on the pinhole(s)'s size and location, as well as the age of the cell.

In some embodiments, the methods provided herein further comprise taking a maintenance action on the one or more electrochemical cells based on the evaluation (step VIII in FIG. 2).

In some embodiments of the aforementioned aspects and embodiments, the monitoring of the cells in the electrolyzer is fully automated. In some embodiments of the aforementioned aspects and embodiments, the monitoring is partially automated. In some embodiments of the aforementioned aspects and embodiments, the whole monitoring is fully automated except for the step of measuring physical parameters and evaluating the components of the cell where the method may be manual, digital, or automated depending on the parameter to be adjusted.

For example, instruction to take maintenance action may be sent manually, digitally, or automatically to one or more valves to adjust the flow of the streams, one or more pumps, one or more compressors, one or more heat exchange units, current controller, and/or one or more heaters or coolers to turn-on/off or open/close to increase or decrease the temperature or pressure value of the process. In some embodiments of the aforementioned aspects and embodiments, the instructions may be sent to a specific location of the one or more components in order to selectively increase or decrease the flow of liquids (to cause changes in the concentration of the ions in the anolyte), the current density, the temperature and/or pressure value at that specific location.

In one aspect, there is provided a system for monitoring condition of one or more electrochemical cells in an electrolyzer, the system comprising:

a voltage acquisition module coupled to each one of electrochemical cells or a group of the electrochemical cells in an electrolyzer and adapted for characterizing a reference voltage range and for acquiring voltage for each one of the electrochemical cells or the group of the electrochemical cells during operation, wherein each one of the electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;

a factor acquisition module adapted for acquiring data related to the factors comprising the current density and the concentration of the metal ions in the anolyte of the one or more electrochemical cells;

a comparison module coupled to the voltage acquisition module and the factor acquisition module, the comparison module adapted to compare the acquired voltage with the characterized reference voltage range based on the factors; and trigger an alarm when the acquired voltage deviates from the reference voltage range.

FIG. 4 illustrates a system 200, for monitoring the condition of one or more electrochemical cells in the electrolyzer, operably connected to the one or more electrochemical cells. The system 200 of FIG. 4 that conducts monitoring of the system 100 of FIG. 1 is described in detail below.

The system 200 may include a computer interface (where monitoring is computer-assisted or is entirely controlled by computer) configured to provide a user with input and output parameters or is automated to control the conditions of the cells, as described above.

In some embodiments of the aforementioned aspect, the system comprises the voltage acquisition module A (as shown in FIG. 4) coupled to each one of the electrochemical cells or the group of the electrochemical cells in the electrolyzer and adapted for characterizing the reference voltage range and for acquiring voltage for each one of the electrochemical cells or the group of electrochemical cells during operation.

In some embodiments of the aforementioned aspect and embodiments, the voltage acquisition module comprises a current controlling module, the current controlling module being adapted to control current in each one of the cells or group of cells at start-up, steady state, shut-down, and/or transient state of the cells. In some embodiments, the current controlling module can be used to vary the current density passing in the cell so as to increase the current supplied to a cell from zero and up to a given optimum value at start-up, or back to zero for a shut-down operation.

For example, in some embodiments, the electrolyzer is arranged with a number of cell groupings; each cell grouping may contain any number of electrochemicals cells. Each cell voltage may be measured by a metal wire. The wires may be concentrated in a multi-cable protected cable through a TFP (Terminal Fuse Protection) device. The voltage acquisition module can thus be used to acquire data from various cell groupings in electrolyzers. For example, the voltage acquisition module can multiplex the signals from each cell grouping by a series of relays, in a sequence for transmission to a personal computer optionally connected in a local network, and in accordance with a given communication setup.

In some embodiments of the aforementioned aspect and embodiments, the system further comprises the factor acquisition module B (as shown in FIG. 4) adapted for acquiring data related to the factors comprising the current density and the concentration of the metal ions in the anolyte of the one or more electrochemical cells. In some embodiments, the voltage acquisition module is adapted for receiving data from the factor acquisition module and based on the data related to the factors, characterizing the reference voltage range. The voltage acquisition module is also adapted for acquiring the voltage of each one of the electrochemical cells or the group of the electrochemical cells during operation.

In some embodiments, the anolyte further comprises salt ions and the factors further comprise concentration of the salt ions in the anolyte of the one or more electrochemical cells. In some embodiments, the factor acquisition module is adapted to acquire data related to the factors comprising the current density, concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, and/or concentration of the salt ions. In some embodiments, the factor acquisition module is adapted to acquire data from in-situ or ex-situ analytical techniques selected from the group consisting of temperature probe (resistance temperature detectors, thermocouples, gas thermometers, thermistors, pyrometers, infrared radiation sensors, etc.), pressure probe (e.g., electromagnetic pressure sensors, potentiometric pressure sensors, etc.), oxidation-reduction potential (ORP) probe, quadruple mass spectrometer (QMS), ATR probe, ultramicroelectrode (UME) probe, gas chromatography (GC), titrator, inductively coupled plasma (ICP) emission spectrometers, electrochemical sensor, volatile organic compound (VOC) sensor, coriolis flow meter, volume probes (e.g., geophysical diffraction tomography, X-ray tomography, hydroacoustic surveyers, etc.), and other devices for determining anolyte composition or the exiting gas composition, e.g., infrared (IR) spectrometer, nuclear magnetic resonance (NMR) spectrometer, ultraviolet (UV)-vis spectrophotometer, high performance liquid chromatographs, inductively coupled plasma mass spectrometers, ion chromatographs, X-ray diffractometers, gas chromatographs, gas chromatography-mass spectrometers, flow-injection analysis, scintillation counters, acidimetric titration, and flame emission spectrometers, etc. It is to be understood that there can be other analytical techniques from where the data can be retrieved and as such all such techniques are within the scope of this disclosure. The one or more analytical techniques are configured for monitoring the concentration of the metal ions and/or salt ions in the anolyte.

In some embodiments, the one or more analytical techniques individually may also have a computer interface configured to provide a user with the collected data about the anolyte composition, current density, temperature, pressure etc. For example, the analytical techniques may determine the concentration of the metal ions and/or the salt ions in the anolyte and the computer interface may provide a summary of the changes in the composition within the aqueous anolyte over time. In some embodiments, the summary may be sent to the system as factor acquisition data or is stored as a computer readable data file or may be printed out as a user readable document. In some embodiments, the summary may be sent to the voltage acquisition module to compute and characterize the reference voltage range.

Similarly, the collective data in the system obtained by the voltage acquisition module and the factor acquisition module may be stored as a computer readable data file or may be printed out as a user readable document.

In some embodiments, the one or more analytical techniques may be configured to determine the parameters of the process, such as, concentration of the metal ions and/or the salt ions at regular intervals, e.g., determining the composition every 1 minute, every 5 minutes, every 10 minutes, every 30 minutes, every 60 minutes, every 100 minutes, every 200 minutes, every 500 minutes, or some other interval. The data retrieved by the factor acquisition module from the one or more analytical techniques may be further processed in the system.

In some embodiments, the system further comprises a computing module within the voltage acquisition module configured to characterize the reference voltage range by computing the data received regarding the concentration of the metal ions in the anolyte from the factor acquisition module.

In some embodiments of the aforementioned aspects and embodiments, the system further comprises the comparison module C (as shown in FIG. 4) coupled to the voltage acquisition module and the factor acquisition module, the comparison module adapted to compare the acquired voltage with the characterized reference voltage range.

In some embodiments of the aforementioned aspects and embodiments, the comparison module is adapted to trigger the alarm, by generating interlock protocol, by generating shut-down protocol, or combinations thereof. The alarm may not be audible and may be detection of an anomaly followed by interlock and/or shut down procedures. Or in some embodiments, the alarm may be an audible sound such as a beep, flash, ring, bell, or the like. After the signal is heard from the system, the user may manually adjust the parameters or the system may send instructions to one or more components to shut-down.

In some embodiments of the aforementioned aspects and embodiments, the comparison module is further adapted to classify the cells as significantly damaged cells, damaged cells, and undamaged cells, based on the comparison.

In some embodiments of the aforementioned aspects and embodiments, the system further comprises a storage module (not shown in FIG. 4) coupled to the voltage acquisition module; the factor acquisition module; and the comparison module, adapted for storing: the reference voltage range for each one of the cells; the acquired voltage for each one of the cells; the concentration of the metal ions in the anolyte of the one or more electrochemical cells; the concentration of the salt ions in the anolyte of the one or more electrochemical cells; current density; and the comparison data.

In some embodiments of the aforementioned aspects and embodiments, the system further comprises a damage evaluation module D (as shown in FIG. 4) coupled to the comparison module, the damage evaluation module is adapted to obtain information from one or more sensors adapted for measuring a physical parameter of each one of the cells classified as significantly damaged cells or damaged cells, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof. In some embodiments, the sensor comprises one of a differential pressure sensor and/or a liquid sensor for measuring a level or flow of liquid in a cell.

In some embodiments, the sensors and the analytical techniques described above may overlap. In some embodiments, the damage evaluation module may be coupled also to the factor acquisition module and may receive data related to one or more factors to measure the physical parameters.

In some embodiments of the aforementioned aspects and embodiments, the damage evaluation module D is further adapted for evaluating the cause of the damage to the cells based on the measurement of the physical parameters. The damage evaluation module D is adapted for evaluating at least one of a position and size of a pinhole in a membrane; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof, using the measured physical parameter for each one of the significantly damaged or damaged cells.

In some embodiments of the aforementioned aspects and embodiments, the system further comprises an electrolyzer maintenance module E (as shown in FIG. 4) coupled to the damage evaluation module and adapted to transmit a signal representative of a maintenance action to be performed on any one of the significantly damaged or damaged cells, the maintenance action being based on the evaluation of the significantly damaged or damaged cells. The maintenance module may operate manually, digitally, or automatically.

In some embodiments of the aforementioned aspects and embodiments, the maintenance module is configured to send instructions to one or more of the components of the damaged cell to adjust the flow rate, current density, and/or temperature/pressure such that the concentration of the metal ions is adjusted, thereby adjusting the acquired voltage to align with the reference voltage range. The one or more components are selected from, for example only, one or more valves, one or more pumps, one or more compressors, one or more heat exchange units, one or more heaters or coolers, power source, rectifier, one or more tanks, and combinations thereof.

In some embodiments, the system may be a computer interface which is configured to provide a user with the collected data about the process and systems 100. One or more of the modules of the system may be part of one or several systems connected to each other. In some embodiments, all of the modules are part of a single computer program encoded to carry out the monitoring of the condition of the electrochemical cells in the electrolyzer.

In some embodiments, the system may be a computer interface that provides a summary of the conditions of the process to the user over time. In some embodiments, the summary is stored as a computer readable data file or may be printed out as a user readable document. In some embodiments, the system comprises a monitor screen to display the reference voltage range, acquired voltage, comparison of the reference voltage range with the acquired voltage, data related to the one or more factors, combinations thereof. In some embodiments, the system comprises a monitor screen that displays the aforementioned one or more components of the system with respect to their location in the cell system; the one or more analytical techniques operating in the cell system; and/or the values of the one or more factors and/or physical parameters with respect to their location in the system. In some embodiments of the aforementioned aspects and embodiments, the system has a monitor screen with a touch screen. The system may be connected to the one or more components as well as the one or more analytical techniques of the cell system through wires or wirelessly.

Computer Program Product

In one aspect, there is provided a computer program product encoded on a non-transitory computer-readable medium, which when executed, causes the computer to monitor condition of one or more electrochemical cells in an electrolyzer, in accordance with the methods and systems described herein.

In one aspect, the computer program product encoded on a non-transitory computer-readable medium, which when executed, causes the computer to monitor condition of one or more electrochemical cells in an electrolyzer, comprises:

instructions executable to characterize reference voltage range for each one of electrochemical cells in an electrolyzer during operation, wherein each one of the electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;

instructions executable to acquire voltage for each one of electrochemical cells in an electrolyzer during operation;

instructions executable to acquire data related to the factors comprising the current density and the concentration of the metal ions in the anolyte during the operation of the one or more electrochemical cells;

instructions executable to compare the acquired voltage with the characterized reference voltage range based on the factors; and

instructions executable to trigger an alarm when the acquired voltage deviates from the reference voltage range.

In some embodiments of the above noted aspect, the instructions executable to trigger the alarm comprise triggering the alarm by sound or otherwise, generating interlock protocol, generating shut-down protocol, or combinations thereof.

In some embodiments of the above noted aspect and embodiment, computer program product further comprises, based on the comparison, instructions executable to classify the cells as significantly damaged cells, damaged cells, and undamaged cells.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to store information comprising the reference voltage range for each one of the cells; the acquired voltage for each one of the cells; the concentration of the metal ions in the anolyte of the one or more electrochemical cells; the concentration of salt ions in the anolyte of the one or more electrochemical cells; current density; and the comparison data.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to obtain information from one or more sensors adapted for measuring a physical parameter of each one of the cells classified as significantly damaged cells or damaged cells, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to evaluate at least one of a position and size of a pinhole in a membrane; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof, using the measured physical parameter for each one of the significantly damaged or damaged cells.

In some embodiments of the above noted aspect and embodiments, computer program product further comprises, instructions executable to transmit a signal representative of a maintenance action to be performed on any one of the significantly damaged or damaged cells, the maintenance action being based on the evaluation of the significantly damaged or damaged cells.

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the present invention, and are not intended to limit the scope of what the inventors regard as their invention nor are they intended to represent that the experiments below are all or the only experiments performed. Various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description and accompanying figures. Such modifications fall within the scope of the appended claims. Efforts have been made to ensure accuracy with respect to numbers used (e.g. amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is weight average molecular weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric.

EXAMPLES Example 1 Monitoring of the Condition of the Electrochemical Cell

The system to monitor condition of the cells in an electrolyzer or a group of electrolyzers is set up by characterizing and saving methods such as, setting up reference voltage range with respect to the concentration of the metal ions and the salt ions in the anolyte, setting up current density, and setting up start-up, steady state, and shut-down procedures. Setting up of the temperature window around desired measurement temperature, setting up maximum temperature equilibration time, setting up cleaning procedure, and setting up measurement procedure may also be done.

The system is set up by setting up the voltage ramp rates (up and down); the voltage dwell time; the voltage amplitude; the number of measurement cycles; and the time between consecutive measurement cycles (measurement rate).

The data analysis algorithm is modified and stored on the processor board.

The measurement method is initiated. The voltage measurement data acquisition rate is set up. When the polarization level of each cell has passed at start-up of the electrolyzer, the voltage distribution of the cells can be established by steadily increasing the current density and taking voltage measurements continuously or at predefined steps. The raw current data is viewed on a graph. The raw data files are stored locally. The system is calibrated and the calibration file is stored on the processor.

The voltage is read at various sampling rates. The acquired voltage data is plotted vs. time and is compared to the reference voltage range based on the concentration of the metal ions. The voltage data is stored locally.

Example 2 Monitoring of the Condition of the Electrochemical Cell

An electrochemical cell was run using the procedure described in Example 1. A reference voltage range was set up based on the current and concentration of the metal ions in the anolyte fed into the anode chamber. Voltage measurements were done continuously to determine that the acquired voltage was within the reference voltage range (as shown in FIG. 5).

Claims

1. A method for monitoring condition of one or more electrochemical cells in an electrolyzer, the method comprising:

characterizing a reference voltage range for one or more electrochemical cells in an electrolyzer during operation, wherein the one or more electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;
acquiring a voltage of the one or more electrochemical cells during the operation;
comparing the acquired voltage with the reference voltage range based on the factors; and
generating an alarm trigger when the acquired voltage deviates from the reference voltage range, thereby monitoring the condition of the one or more electrochemical cells in the electrolyzer.

2. The method of claim 1, further comprising determining the concentration of the metal ions in the anolyte of the one or more electrochemical cells and based on the determination, characterizing the reference voltage range for the one or more electrochemical cells.

3. The method of claim 2, comprising determining the concentration of the metal ions in the feed anolyte and/or exit anolyte from the one or more of the electrochemical cells in the electrolyzer.

4. The method of claim 1, wherein the anolyte further comprises salt ions and the factors further comprise concentration of the salt ions in the anolyte during the operation of the one or more electrochemical cells.

5. The method of claim 4, wherein the salt ions are alkali metal salt ions or alkaline earth metal salt ions.

6. The method of claim 1, wherein the concentration of the metal ions in the anolyte comprises concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, or combinations thereof.

7. The method of claim 1, wherein the metal ion is copper (Cu).

8. The method of claim 1, wherein the concentration of the metal ions comprises concentration of Cu(I), concentration of Cu(II), concentration of total Cu(I) and Cu(II), ratio of the concentration of Cu(I) to Cu(II), or combinations thereof.

9. The method of claim 1, further comprising obtaining data from in-situ or ex-situ analytical techniques and based on the data determining the concentration of the metal ions and/or the concentration of the salt ions in the anolyte during the operation.

10. The method of claim 9, wherein the in-situ or ex-situ analytical techniques comprise coriolis meter, titration of the anolyte, inductively coupled plasma (ICP) technique, ultra-microelectrode (UME) technique, or combinations thereof.

11. The method of claim 1, wherein the operation comprises start-up, shut-down, steady state, transient state, or combinations thereof.

12. The method of claim 1, wherein generating the alarm trigger comprises generating an alarm to analyze the one or more electrochemical cells in the electrolyzer; generating interlock protocol; generating shut-down protocol; or combinations thereof.

13. The method of claim 1, further comprising classifying the one or more electrochemical cells as significantly damaged, damaged, or undamaged, based on the comparison or the alarm trigger.

14. The method of claim 13, further comprising measuring a physical parameter of the one or more electrochemical cells classified as significantly damaged or damaged, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof.

15. The method of claim 14, further comprising based on the measurement, evaluating: size and position of a pinhole in a membrane in the cell; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof.

16. The method of claim 15, further comprising taking a maintenance action on the one or more electrochemical cells based on the evaluation.

17. A system for monitoring condition of one or more electrochemical cells in an electrolyzer, the system comprising:

a voltage acquisition module coupled to each one of electrochemical cells or a group of the electrochemical cells in an electrolyzer and adapted for characterizing a reference voltage range and for acquiring voltage for each one of the electrochemical cells or the group of the electrochemical cells during operation, wherein each one of the electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;
a factor acquisition module adapted for acquiring data related to the factors comprising the current density and the concentration of the metal ions in the anolyte of the one or more electrochemical cells;
a comparison module coupled to the voltage acquisition module and the factor acquisition module, the comparison module adapted to compare the acquired voltage with the characterized reference voltage range based on the factors; and trigger an alarm when the acquired voltage deviates from the reference voltage range.

18. The system of claim 17, wherein the factor acquisition module is adapted to acquire data related to the factors comprising the current density, concentration of the metal ions in the lower oxidation state, concentration of the metal ions in the higher oxidation state, ratio of the concentration of the metal ions in the lower oxidation state to the metal ions in the higher oxidation state, and/or concentration of the salt ions.

19. The system of claim 17, further comprising a damage evaluation module coupled to the comparison module, the damage evaluation module adapted to obtain information from one or more sensors adapted for measuring a physical parameter of each one of the cells classified as significantly damaged cells or damaged cells, wherein the physical parameter comprises current distribution, coloration of liquid exiting the cells, pressure of gas in the cells, pressure or flow of liquid entering the cells, pressure or flow of liquid exiting the cells, or combinations thereof.

20. A computer program product encoded on a non-transitory computer-readable medium, which when executed, causes a computer to monitor condition of one or more electrochemical cells in an electrolyzer, the computer program product comprising:

instructions executable to characterize reference voltage range for each one of electrochemical cells in an electrolyzer during operation, wherein each one of the electrochemical cells comprise an anode in contact with an anolyte comprising metal ions, and wherein the reference voltage range is dynamic dependent on factors comprising current density and concentration of the metal ions in the anolyte of the one or more electrochemical cells;
instructions executable to acquire voltage for each one of electrochemical cells in an electrolyzer during operation;
instructions executable to acquire data related to the factors comprising the current density and the concentration of the metal ions in the anolyte during the operation of the one or more electrochemical cells;
instructions executable to compare the acquired voltage with the characterized reference voltage range based on the factors; and
instructions executable to trigger an alarm when the acquired voltage deviates from the reference voltage range.

21. The system of claim 17, wherein the comparison module is farther adapted to classify the cells as significantly damaged cells, damaged cells, and undamaged cells, based on the comparison.

22. The system of claim 17, wherein the voltage acquisition module comprises a current controlling module, the current controlling module being adapted to control current in each one of the cells or group of cells at start-up, steady state, shut-down, and/or transient state of the cells.

23. The system of claim 19, wherein the damage evaluation module is adapted for evaluating at least one of a position and size of a pinhole in a membrane; position of blockage of the flow in the cell; position of a pinch in feed line; fouling of the membrane; construction of the cell; welded points in the cell; or combinations thereof, using the measured physical parameter for each one of the significantly damaged or damaged cells.

24. The system of claim 23, further comprising an electrolyzer maintenance module coupled to the damage evaluation module and adapted to transmit a signal representative of a maintenance action to be performed on any one of the significantly damaged cells or damaged cells, the maintenance action being based on the evaluation of the significantly damaged cells or damaged cells.

Patent History
Publication number: 20180245226
Type: Application
Filed: Feb 20, 2018
Publication Date: Aug 30, 2018
Applicant:
Inventor: Ryan J. Gilliam (San Jose, CA)
Application Number: 15/900,343
Classifications
International Classification: C25C 7/06 (20060101); C25C 1/12 (20060101);